CK5
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86 Coal Burner ...
- Thread starter onedaatmc
- Start date
6.2 engines are cold-blooded, but you should be able to drive it year-round. I was driving mine this week, and I'll venture that our location is probably colder than yours on average. Glow plugs are the most likely culprit.
I would go a step further and use the ohmmeter instead of the test light. Disconnect the wires going to each plug and measure resistance between each plug's connector and ground. A good plug will read <1 Ohm. New AC Delco 60G plugs will measure 0.2 Ohms. Higher resistance values will produce less heat. A burned-out plug will read as infinite resistance (open circuit).
If you don't have at least a few good plugs, the engine will not start (period). I don't drive my truck during the snowy season, so I haven't bothered replacing my plugs. They are failing, one-by-one, and the truck started this week on approximately 4 cylinders (so it's either time to park it for the season or replace the plugs
). My Suburban, with new plugs, fires right off even in the cold weather.You don't have to replace all your plugs, but plugs are not all equal. AC 60G and Bosch Duraterm plugs are both good options, and they are both rated for continuous duty. The original AC 9G plugs that came with these engines are rated for short bursts. Your 1986 controller should be running a cycle of 2 seconds on and 2 seconds off (approximately). With new plugs, you can run a single long cycle, warming your engine quickly, rather than waiting for several short cycles. This is a nice bonus if you are running a manual switch, or if you feel like modifying your glow plug controller (or replacing it with a later model one).
FWIW, A group performed some testing of glow plugs in a stand (no heat sink to cool them), and recorded how long it took for each plug to burn out. They found that Duraterms lasted longest in this configuration (while 60G plugs also did well). The Bosch plugs use a 10mm head, while the 60G plugs use a 3/8" head. Makes for great fun if you have mismatching plugs on the engine (especially on the 6.5TD, where you can't easily see the plugs due to the turbine setup).
For old plugs, anything more than a few seconds will burn them out. So it's possible that you had some fine (old) plugs, and running the cycle for a minute burned the rest of them out.
Or you could have my CUCV's problem: It says it's glow-plugging when it's actually not. Really hard to start that way.
Yes, this is correct. Just make sure you measure each plug individually (and not the harness). And the lug on the glow plug is not connected to the outside casing (which is grounded). So make sure you are measuring the lug and not the case. You can use the case as your ground reference.
onedaatmc
1/2 ton status
ok .... sound like plugs are cheap , I could just replace them and be done then huh ... and I assume their an easy take out ? and replace ?
onedaatmc
1/2 ton status
ok ... I'll have a look ... I assume their easy to find , like in a similar location like a spark plug ? one for each cylinder ?
Yep. The ends do tend to break off and stay inside. Might be just the ceramic, might be a piece of the toaster wire, too. Either way, there's not much you can do about it. They look like small spark plugs.
Here's a picture from my Suburban thread:
New plug, old plug. Both are AC Delco 60G. Note that the old one is shorter.
New plug, old plug. Both are AC Delco 60G. Note that the old one is shorter.
So this is something I don't know. If you are having trouble getting it out. Couldn't you pull the injector and get most of what breaks off through the injector hole? My buddy who was a SeaBee talked about using a claw hammer or reaching though the injector hole to smash the end back flat. Luckily I haven't had these problems.
Yes it is possible to pull the injector to get the busted pieces out,using needle nosed pliers,bubble gum on a stick,or a shop vac,etc--but be aware on an older engine,the fuel lines will likely be rusty and pitted,and may not survive being disturbed...also its very easy to snap off the return line nipples on an injector ,if the socket tilts or slips while your loosening it..
Neither the fuel lines or injectors are cheap ,and good used ones are hard to find,especially in the rust belt states..
I've had one glow plug break while the engine was running in my pickup--it clattered like a bad lifter for several miles,after I first heard the noise and determined it still had good oil pressure,I decided to just drive it the 4 miles home...sounded awful!..
But I did get home,and when I was close enough to walk the rest of the way,I dropped it in first and floored it until it hit the govenor limits--figured it would either blow up--or blow out the glow plug bits...it quieted down after that,so I'm assuming it just blew the chunks out the exhaust..from that day on I hear a lifter tap noise till the engine warms up good after a cold start..may have bent a pushrod slighty or some other valve train part..but it runs the same..
The engine seems no worse for the wear,but I wouldn't doubt the cylinder or valves could well have suffered some trauma..
I read stories online about Humvees having them snap off,and the army mechanics simply started the engine and revved it up to blow out the chunks,with no apparent damage,but I wouldn't want to try it..also read where some tried leaving the plugs unscrewed that had mushroomed tips,and ran the engine to let the compression and heat blow them out like bullets....that sounds risky too..
..
After I replaced that plug that failed I noticed half of it was gone,and it was an Autolite 1110 plug,the rest were AC 60G --one diesel mechanic I asked said he's seen more than one plug fail like that and it could be "mixing" different brands or part numbers.like 60G's and 9g's might send more current to the "oddball" and cause it to burn up--also said he would not use 9G or other stock glow plugs with a manual override either,they are almost sure to mushroom and cause grief when its time to remove them..
I've had to replace my glow plugs 3 times in 12 years,they ROT AWAY before they fail electrically in most cases--had to toss several "good" ones out because I was afraid I wouldn't be able to get them OUT later,the 3/8 "hex was whittled away to nothing,I had to hammer a 5/16" 6 point socket on them to get them loose!--was afraid I wouldn't be able to grip them,or snap the hex off the body of the plug...that would suck if it happened on the rear most cylinders you cant get at easily...
Neither the fuel lines or injectors are cheap ,and good used ones are hard to find,especially in the rust belt states..
I've had one glow plug break while the engine was running in my pickup--it clattered like a bad lifter for several miles,after I first heard the noise and determined it still had good oil pressure,I decided to just drive it the 4 miles home...sounded awful!..
But I did get home,and when I was close enough to walk the rest of the way,I dropped it in first and floored it until it hit the govenor limits--figured it would either blow up--or blow out the glow plug bits...it quieted down after that,so I'm assuming it just blew the chunks out the exhaust..from that day on I hear a lifter tap noise till the engine warms up good after a cold start..may have bent a pushrod slighty or some other valve train part..but it runs the same..
The engine seems no worse for the wear,but I wouldn't doubt the cylinder or valves could well have suffered some trauma..
I read stories online about Humvees having them snap off,and the army mechanics simply started the engine and revved it up to blow out the chunks,with no apparent damage,but I wouldn't want to try it..also read where some tried leaving the plugs unscrewed that had mushroomed tips,and ran the engine to let the compression and heat blow them out like bullets....that sounds risky too..
..After I replaced that plug that failed I noticed half of it was gone,and it was an Autolite 1110 plug,the rest were AC 60G --one diesel mechanic I asked said he's seen more than one plug fail like that and it could be "mixing" different brands or part numbers.like 60G's and 9g's might send more current to the "oddball" and cause it to burn up--also said he would not use 9G or other stock glow plugs with a manual override either,they are almost sure to mushroom and cause grief when its time to remove them..
I've had to replace my glow plugs 3 times in 12 years,they ROT AWAY before they fail electrically in most cases--had to toss several "good" ones out because I was afraid I wouldn't be able to get them OUT later,the 3/8 "hex was whittled away to nothing,I had to hammer a 5/16" 6 point socket on them to get them loose!--was afraid I wouldn't be able to grip them,or snap the hex off the body of the plug...that would suck if it happened on the rear most cylinders you cant get at easily...
Yes, you can pull the injector, and that's what I would do if a large enough piece of the plug was stuck inside. In my case, I was missing small pieces of crumbly ceramic. I don't think I could have found the pieces even if I had disassembled the ignition chamber. It would take a pretty large chuck of plug to warrant disassembly of the upper section of the engine (as Bob described above).
The ignition chamber is open on the bottom, so any pieces that come off are likely to fall into the cylinder (unless they're quite large). At some point it's not worth a full engine teardown just to see if you can find some ceramic dust that probably blew out the exhaust pipe 10,000 miles ago.
onedaatmc
1/2 ton status
I should also say that the engine says Goodwrench , which I assume isn't stock ... I'm thinking a crate motor swap was done at some point, so maybe the glow plugs aren't that old is what I'm thinking, the other thing to think about is that slowly but surely the electrical is failing , well sort of , now all my factory gauges don't work , the only gauges that do are the aftermarket oil press, the exhaust temp and the turbo boost ... yes it has a Banks in it ...so don't know if it's a short somewhere ... sometimes the glow plug light comes on or not as well when pressing the manual glow plug deal ....
At least one of my trucks also has the issue with the glow plug light sporadically not illuminating while the plugs are running. My manual switch runs directly to the relay, so the plugs are warming. But the bulb is still connected to the old controller. It usually lights appropriately. But not always.
Yes, Goodwrench would indicate a non-original engine. So would your Banks kit. :P
If the plugs are of a non-continuous type, it may not matter how young they are. If you've been running long cycles on the glow plug switch, their expected lifespan is pretty short. Even good plugs don't last forever. The burned-up 60G plugs that I pulled from my Suburban were still fairly shiny. I don't think they were in there for years and years.
Have you checked to see that all of the plugs are actually getting 12V when you throw the switch? That would be the second thing that I checked (after checking resistance across each plug).
